This morn replaced fuel filter as it was as old as the car hoping it was that, well the bad news its not. Still doing the same. I can rev it to full but doing the same ,on idle up down up down. So any ideas please people.
I dont think its the coil pack as it done that before twice and it dont feel the same as when that went .
All cylinders work as I've disconnected at injectors one by one and there was no change to the problem ,so im a bit stumped to whats wrong ???
Any help i would be most grateful as im under a lot of stress at the moment so cant wrap my head around the problem as i normally would. Thank you harry
just proves the stress makes it so you cant see the wood for the trees ! i went to check idle speed motor and what did i find , well the lead to the air flow censor on the throttle body was hanging off DOH !!! well the metal holding clip was missing, lucky ive got a spare so refitted it, disconected battery for 10 min, reconnected it started her up and ticked over perfect , revved her and she was a little slow to react but after half a dozen trys she was back to normal, so took her out for a drive city road then motorway, well shes running better than she ever has, so the new fuel filter i walked 4 miles to get this morning was worth it, hopeful mileage will improve as 37-40 for £10 fuel is what ive been getting, but then im heavy footed and its an 1.8 16v fuel drinker. but i do love her and peoples faces when they see a Xantia flying along. as lets be honest its an old mans car careful drivers. though i do keep to speed limits as got 6 points for a ton on the motorway a few years ago, but i do get to the limit as fast as i can lol as hate hanging about and i promised her i would use her power till she dies,as 1.8i 16v is a sports engine that likes to rev,so she could have a good send of before the scrap yard, mot due next week think it maybe her last, saving cash soon to buy a new Xantia, after that one who know what i will drive, would like a C5 as i love the hydraulic suspension on the Xantia holds the road so well and corners beautifully. Anyway people thank you so much for your help and advice. your good people taking the time to do so. happy safe driving, 
Your "air flow sensor" is actually the MAP sensor which measures manifold absolute pressure.... a critical sensor for proper running of the engine, it needs it to work out how much air is being sucked in and therefore how much fuel to inject... glad you got it sorted.
